Tag Archives: Bridges

Twin Cities, MN

I had a few spare weeks recently, and decided to go on a cross-country trek to visit some friends. I also took the opportunity to take in some civil engineering landmarks along the way. First stop was Minneapolis/St. Paul, Minnesota. Had a great time visiting my college buddy Garrett, now a grad student at U of M. We passed by the Civil Engineering building on campus, a building residing almost completely underground. For it’s unique design it was awarded with the Outstanding Civil Engineering Achievement Award by ASCE in 1983.

I visited the new 1-35W Mississippi River Bridge, the replacement bridge on the site of the disastrous 2007 bridge collapse. Improper design as well as large loads from construction equipment and extra layers of pavement caused the original bridge to collapse. Nearby, I walked across the Stone Arch Bridge of Minneapolis, overlooking the only waterfall on the Mississippi river. Built in 1883 and named a Historic Civil Engineering Landmark, the bridge served as a railway bridge but now serves as a pedestrian and bicycle path across the Mississippi. In the area are many parks that serve the historic district and showcase the history of the water-powered mills that put the Twin Cities on the map.

It’s always exciting to see public transportation improvement projects, and it was neat to see the construction of new light rail stations by the local Metro Transit in St. Paul. We also visited the Town Hall Brewery and attended the Beer Dabbler Winter Carnival 2012.

Colorado

Next stop was Colorado. Not too many civil engineering landmarks on this leg of the trip. Instead, I had the wonderful opportunity to have some family in the area expose me to some really neat experiences. I went ice-fishing, fed buffalo, visited Odell Brewing, and sat in on a volunteer-firefighting training seminar. For those most interested in the sciences, here’s a nerdy exposition: you can calculate the thickness of clear ice h (inches) that can withstand failure from a load of p (tons) with the following formula: h = 4√p

There’s all sorts of other factors you can throw in for safety, and if you plan on driving out on the ice, you should probably give these a good read:

Los Angeles, CA

My last stop was LA, visiting another NC State friend and former roommate, Joe. Much warmer than the previous stops, I enjoyed the beautiful sunny weather of Pasadena. I visited Venice Beach, the infamous Hollywood sign, Griffith Park Observatory, El Pueblo, Hollywood Boulevard, La Brea Tarpits, IO West Improv Club, In-N-Out Burger, and Point Fermin Lighthouse.

Of course, my visit to the locale wouldn’t do my “engineering” trek justice if I didn’t review local transportation resources. I rode both the Metro Bus and the Metro Rail, visited Union Station, and found it all to be exceptional for my use as a tourist. Joe commutes to and from work daily via Metro Rail and bicycle (which he can bring on the train) and finds them more than adequate. I was impressed with the timeliness, cleanliness, and usefulness. I only wish we had this kind of rail in Raleigh.

I also noticed the use of ramp meters both here and in Twin Cities. These are not a congestion tool we currently use in North Carolina, so I sent a quick email to Dr. Hummer, professor at NC State, with some questions on use cases and statistics. He responded rather quickly and gave me great information on the topic. They can keep the mainline traffic moving better than Level of Service “F”, preventing a 100-300 vehicles per hour per lane drop in capacity. They break up “platoons” of cars, and can decrease travel time up to 10%. In North Carolina, it’s been easier to add conventional capacity in the past, but NCDOT may need to look at ramp meters more closely for use on I-77 in Charlotte and areas around RTP.

All in all, the trip was very rewarding, and I can’t wait for the next opportunity to do a similar trip in the future. Special thanks to family and friends for taking time to spend with me and making my trip possible!

Bonus Footage

With the technology we’ve had up to today, it’s been very difficult to account for the weathering of our bridges, buildings, and other structures. State Departments of Transportation spend millions of dollars every year in testing, but current methods include many assumptions and are not always accurate. Thus accidents happen like the collapse of the Minneapolis I-35 Bridge that crosses the Mississippi.

New sensors to monitor performance are starting to become more common, but they only help if the sensor is placed at the source of a potential problem. I remember when I was working at the Constructed Facilities Laboratory at NC State, we would place sensors on key areas of beams and columns and test them for failure. Fortunately, we knew where each column and beam would fail, but bridge-systems are slightly more complicated.

New funding from the National Institute of Standards and Technology and the Michigan DOT is being spent on next-generation monitoring systems like “skins”. These skins can be painted on or exist in a layer of concrete. New wireless technology will help bring the cost of these systems down significantly, and wireless sensors have performed well in the East. You can read the full article that goes further in depth at Scientific American.

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Mike Roselli, PE

Mike Roselli is a Civil Engineer and consultant, licensed in the States of NC, SC, GA, and FL, and is focused on providing land development services to clients building in the Triangle Area. He currently resides in Cary, NC.